Study of US veterans shows key differences in neural activity
FRIDAY, April 3 (HealthDay News) -- Someday, doctors might use brain scans to diagnose post-traumatic stress disorder (PTSD), according to researchers who conducted tests on 42 American soldiers who'd recently served in Iraq or Afghanistan.
The male and female soldiers had comparable levels of combat exposure. They were divided into two groups, those with PTSD (22) and those who didn't have the condition (20); fMRI was used to examine the brain patterns of the soldiers while they performed a three-part, short-term memory task that included distractions.
The task is designed to measure the ability to stay focused, which is reduced in people with PTSD.
The researchers noted a number of brain activity differences between the PTSD group and the non-PTSD group, such as in the dorsal lateral prefrontal cortex, an area that plays a role in the ability to stay focused. While doing the memory task, the soldiers with PTSD performed more poorly when they were shown both traumatic and neutral photos, while the soldiers without PTSD were only distracted by the traumatic photos.
"This sensitivity to neutral information is consistent with the PTSD symptom of hypervigilance, where those afflicted are on high alert for threats and are more distracted by not only threatening situations that remind them of the trauma, but also by benign situations," study leader Dr. Rajendra Morey, an assistant professor of psychiatry at Duke University and director of the neuroimaging lab at Durham Veterans Administration Center, said in a news release.
"This has not been seen at the brain level before. If further research confirms this preliminary finding, this pattern could be useful in distinguishing the PTSD brain," Morey said.
The researchers also noted marked differences in an area in the medial prefrontal cortex that governs sense of self. This area showed a much higher level of activity when the soldiers with PTSD looked at combat photos, but showed little response in those without PTSD.
"This is consistent with what we see behaviorally in PTSD, where people with the disorder are much more likely than others to connect traumatic triggers to events that have increased personal relevance, such as the combat situations in war veterans," co-author Dr. Florin Dolcos, an assistant professor of psychiatry and neuroscience at the University of Alberta in Canada, said in the news release.
The study was to be presented Friday at a World Psychiatric Association meeting in Florence, Italy.
"As technology improves, imaging research is increasingly providing insights into the brains of people with post-traumatic stress disorder, pointing to potential biological markers distinguishing the PTSD-affected brain," Dolcos said. "The field is still in its infancy, but this raises the possibility that one day we may be able to see the disorder in the body as plainly as we now can see conditions such as heart disease and cancer."
The U.S. National Institute of Mental Health has more about PTSD.
-- Robert Preidt
SOURCE: World Psychiatric Association, news release, April 3, 2009
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